Not Applicable
1. Technical Field
This invention relates to the field of aircraft displays and more specifically to the representation of wires detected by a wire detection system as seen by an aircraft flight crew.
2. Background Art
Electronic displays are replacing mechanical flight instruments in aircraft (glass cockpit) at an ever-increasing rate. These electronic displays typically display pictorial representations (display formats) of existing instruments, but can also display other formats such as checklists or diagnostics. There are three basic types of aircraft instruments. First, instruments such as altimeters and oil pressure indicators use either pointers or numerical readouts to represent certain aircraft parameter such as altitude or oil pressure. Second, a horizontal situation indicator (HSI) shows a god""s eye view of the aircraft with respect to the earth; digital maps also use this god""s eye view representation. Third, an attitude indicator (ADI), also known as a vertical situation display, shows a pilot""s eye view looking out of the aircraft cockpit; ADI symbology includes simulated sky (blue), earth (brown), and an artificial horizon.
The development of display formats for aircraft flight displays is a fairly rigorous involved process that involves many engineering disciplines including human factors, safety, and avionics design. In the civilian field, the Federal Aviation Administration (FAA) must approve the display formats for all aircraft primary flight instruments such as airspeed, attitude, and altitude. The FAA has issued guidelines for the use of color and other symbol characteristics on electronic flight displays in FAA Advisory Circular 25-2. For military aircraft, the display formats are generally developed during a series of cockpit control working group (CCWG) meetings that consider both civilian and unique military mission requirements.
Graphical display formats that represent pictorial views of conventional mechanical aircraft instruments are known in the prior art. Konicke et al U.S. Pat. No. 4,860,007, Aug. 22, 1989, for example, teaches an integrated primary flight display that includes airspeed, attitude, and altitude on a single format. Further, a prior art attitude director indicator (ADI) display format is shown herein FIG. 1. In the center of the format, an aircraft is symbolically represented, made up of a left wing 1, a right wing 2, and a nose 3. A sky region 11, colored blue, an earth region 12, colored brown, and a horizon line 13, colored white symbolically represent the environment scene outside the aircraft. Aircraft attitude is represented by a moving pitch ladder 14 and a roll pointer 15 in conjunction with a roll scale 16. Basic operation of aircraft attitude indicators is well known in the art and will not be discussed further herein.
The problem of helicopter wirestrikes has existed for many years and has been costly in terms of military hardware and human lives. Loss of helicopters and crew due to strikes against obstacles such as pylons, radio masts and cables is a very serious problem, since actual missions, training exercises and maneuvers of helicopters call for flight profiles below 100 meters and in most cases at or below tree top level. In particular, profiles for combat, search, and rescue missions of military helicopters demand high-speed flight at low altitude for operation below the radar horizon. These helicopters make maximum use of terrain masking to avoid detection. Obstacle avoidance during daylight operation is mainly by visual observation and at night by means of night vision goggles and thermal imaging systems.
Taught in the prior art are various methods and systems that are designed to detect wires, specifically for use in helicopters, such as disclosed in Koechner U.S. Pat. No. 4,902,126, Feb. 20, 1990. However, none of the prior art systems disclose any specific method, apparatus, or display format for displaying detected wires to an aircraft pilot.
My invention consists of an improved vertical situation display apparatus with associated display formats for quickly conveying to an aircraft pilot the output from a wire detection system.
A vertical situation display apparatus in accordance with my invention is especially suitable for helicopters that are conducting low-level operations near populated areas. Advantageously, this invention can be combined with an active laser wire detection system. Also advantageously, my invention can be implemented on non-glass cockpit aircraft by installation of a bezel ring on one or more of the existing attitude director indicators (ADI).